Medicine (St Vincent's) - Theses

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    Diabetes telephone coaching study: a randomised controlled trial and economic analysis
    Varney, Jane ( 2013)
    Aims: The randomised controlled trial (RCT) aimed to assess the efficacy of telephone coaching on glycaemic control, risk factor status and adherence to monitoring requirements in patients with poorly controlled type 2 diabetes (T2DM), both at the intervention’s conclusion (six months) and in the post-intervention period (12 months). The study also involved a cost-effectiveness analysis of the intervention, both in a within-trial setting and in a 10 year modelled scenario. Finally, this study sought to estimate the annual cost of treating Australians with poorly controlled T2DM. Method:Participants with T2DM, HbA1C >7% (n=94) were randomised to receive usual care plus six months of telephone coaching, or usual care only. Coaching involved assessment, education and goal setting regarding diet, exercise, medications and adherence to diabetes monitoring requirements. The primary outcome was HbA1C at six months. Secondary outcomes included HbA1C at 12 months and other physiological and monitoring measures. The within-trial economic analysis used cost and efficacy data collected between baseline and six months of the RCT to estimate the cost-effectiveness of the telephone coaching intervention, compared to usual diabetes care. The primary outcome was an incremental cost effectiveness ratio, expressed as cost per quality adjusted life year (QALY) saved. Items costed included those attributable to medication use, general practitioner presentations, outpatient appointments, emergency department presentations, inpatient admissions and delivery of the intervention. To estimate the annual cost of treating a person with T2DM, six-monthly costs of all participants were doubled to reflect the annual cost. The modelled economic analysis used the UKPDS Outcomes Model to extrapolate outcomes collected at six months in the RCT over 10 years, assuming the ongoing delivery of the telephone coaching intervention. Outcomes included life expectancy, quality-adjusted life expectancy (QALE) and costs. A 5% discount rate was applied to all future costs and benefits. Sensitivity analyses were conducted to reflect uncertainty surrounding key input parameters. Results: The six month intervention contributed to significant improvements in HbA1C (p=0.03), fasting glucose (p=0.02), diastolic blood pressure (BP) (p=0.03) and physical activity (p=0.02). At six months, adjusted mean HbA1C in the intervention group was 7.7% (7.4 to 8.1) compared to 8.5% (8.1 to 8.8) in controls. Intervention group participants also improved their compliance with routine foot checks and pneumococcal vaccination by six months and retinal screening by 12 months. However, the intervention’s effects on glycaemic control had disappeared by 12 months. For the within-trial economic analysis, the intervention was dominated by the control condition. This is because six monthly diabetes-related costs in the intervention group were significantly higher than the control group, $5403 versus $2260, p=0.009. Owing to one death, the intervention group also experienced a non-significant decline in health utility, -0.01 (-0.03-0.01), equating to a reduction in QALE of 0.005. The estimated mean annual cost of treating a person with poorly controlled T2DM was $7020. The intervention dominated the control condition in the modelled economic analysis, contributing to cost savings of $3327 and non-significant improvements in QALE (0.2 QALE) and life expectancy (0.3 years). The intervention also dominated the control condition in most sensitivity analyses. When the baseline imbalance in terms past history of stroke was controlled, the intervention remained highly cost-effective at a cost of $4365 per QALY saved. Conclusions: Telephone coaching improves glycaemic control and adherence to complication screening in patients with poorly controlled T2DM. The effects were not sustained in the post-intervention period, therefore strategies that facilitate the maintenance of intervention gains are required to improve long term outcomes. The intervention was not cost effective during the within-trial period, but over 10 years, the intervention’s cost was predicted to be fully recovered through cost savings from the prevention of downstream morbidity. The estimated annual cost of treating a person with T2DM updates former cost estimates that were based on data collected over 10 years ago. Collectively, these results are of major relevance to clinical practice, public health practice and health policy. Findings from this study support the need for a larger, prospective multi-centre trial of telephone coaching to confirm both the clinical and economic benefits prior to their implementation in routine clinical practice.